Sally Williams @ Fab Academy 2015

Assignment: 

• Design and build a wired &/or wireless network connecting at least two processors

Background

This week, it was suggested by our tutors that it might be an opportune juncture to present to each other, our current vision of our individual final projects, including our understanding of what inputs and outputs we would need to achieve our objectives.

This was a great idea, as in this way, we benefitted by:

• receiving constructive feedback on our concept;
• receiving questions to help reveal or deepen areas we may not have considered;
• knowledge from our tutors on electronic/maufacturing know-how;
• learning more about what technology would be required (hardware/software);
• reflecting on our Networking and Comms requirements for this module.

As a beginner in electronics, for the Networking and Communications assignment this week, I chose to make 3 boards as part of the hello world example. The purpose of this hello world example is to network several boards together in the form of a serial communication bus (as opposed to parrallell communication - think two-way country roads  vs 8 lane motorway). The bridge board (which is also a node) is connected to a computer via a FTDI cable. The two other node boards are connected to the bridge board.

To make efficient use of milling time and materials on the Modela, it was suggested that all the two different types of boards required for our group were milled in succession, on a single larger board. This meant that we all hit the soldering stations at the same time and were able to be more efficient.

For reference, here below, are the sample boards (bridge and node) used for this week's assignment. It was noted that the only difference between the two boards was the FTDI connector added on the 'bridge':



Below, the boards have been milled, soldered.
Each board would need to be given a node ID number or "character" (ready to be identified in the programming):



A visual inspection was made of all boards, and they appeared ready for cable connection and programming. 

Programming the boards (see tutorial)

This involved downloading the "hello.bus.45.c" and "makefile" onto my desktop, saving them into a dedicated folder, then renaming the downloaded "hello.bus.45.make" as "makefile".

The C code file was modified so that each of the nodes (including the bridge) could be identified as a unique "character" on the network and communications (as mentioned earlier). So, starting with identifying the bridge as "0", in turn we identify node "1" and then, furthest away, node "2". This is shown in more detail in the screen grab from the tutorial below:




I connected my Fab ISP to the network, connecting power from my laptop, and succesfully programmed each board in turn.


  

The next stage was to use the "serial monitor" in Arduino to communicate with my network. Again, I inlcude a screen grab of the instructions from the tutorial to do this. See screen grab below:



Here are the successful results from the serial monitor test:



When character "0" was pressed in the serial monitor, the led would flash on the bridge (named "0"). When character "1" was pressed, the led would flash on node "1", etc.